Mirror mountings are designed to structurally support a mirror and reduce vibration in use. Full plastic monoblock base brackets have been used in the past, but have not provided the structural stiffness necessary to eliminate visible vibration of the mirror assembly, thereby making the reflected images difficult to see. In order to reduce vibration, an aluminum die cast carrier has been used to rigidify the mirror mounting and provide adequate stiffness for the mirror assembly. Such fully die cast parts are heavy and expensive to produce given the materials used and the overall die casting process. Further, a bulky mirror-mounting structure that may provide sufficient structural rigidity is more likely to cause vibrations during vehicle travel as well as an increase in overall aerodynamic drag.
Mirror attachment assemblies known in the art have used long steel screws as metallic reinforcements for providing the rigidity needed to support an external mirror mount. Further, mirror bases with a carrier element made from a two-layer composite material and an outer layer made from a synthetic material have been used wherein a rigid inner core is made from a material mixture that includes a synthetic material which is injected into the outer layer. The carrier element is then partially encompassed by a synthetic material outer shell. The fully die cast metal mirror bases generally included outer shell components which are non-supporting and provide only visual aesthetic function, rather than any actual supporting functionality.
Thus, there is a desire to provide a mounting assembly for an external side view mirror as mounted on a door panel to fully support the mirror under abusive loading, wherein the mirror mounting assembly provides sufficient rigidity, stiffness and loading performance to reduce vibration in use, and further provides a lower cost and lower weight solution as compared to fully die cast aluminum or ZAMAK mountings. A low cost manufacturing process for making such a mounting assembly is also desired.